Airbus advice to pilots on speed, page 1

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Topic started on 5-6-2009 @ 09:58 AM by solidshot

Plane maker Airbus has reissued emergency guidelines to pilots after experts said a missing Air France jet may have had false speed measurements. French air accident investigators said automatic messages broadcast by the jet in its final moments showed the plane's systems were giving different readings.

BBC

If Airbus feel that the accident could have been caused or aggravated by instruments giving a false reading and seem to think it may happen again as seemingly shown here should the aircraft not be grounded until this problem is fixed?

reply posted on 5-6-2009 @ 10:23 AM by Hastobemoretolife

Personally I think they are just throw crap at a wall to see what sticks.

It wouldn't be very good for business if they came out and said we don't know what happened.

But yes I believe they should ground all the planes and check out the air speed gauge, that is one of the main gauges you need to fly.

This is a really crazy story. Even if they are able to recover the black boxes and something really crazy happened they won't tell us, they'll just cover it up.

reply posted on 5-6-2009 @ 10:24 AM by getreadyalready

reply to post by solidshot

I don't think they need grounded. It had to do with the narrow window of stall speeds at high altitude. Near the ground in a landing configuration, the plane stalls in the 130 knot range (don't know exact number, a light of pilots on this site can probably elaborate).

In cruising configuration at high altitude, the stall speed is very close to the cruising speed. In addition, it is standard procedure to slow when entering a thunderstorm, and therefore the plane is even closer to the stall speed.

If turbulence puts the plane into an unusual attitude, it may not be possible to recover. The odd readings from all the sensors just before this plane disappeared, may have indicated just such an event.

Therefore, they have changed procedure for entering a thunderstorm; they will no longer slow the speed.

reply posted on 5-6-2009 @ 10:54 AM by Manouche

Airbus has emitted an AIT (Accident Information Telex).
It seems it's a routine procedure after an airplane accident.

reply posted on 5-6-2009 @ 12:16 PM by C0bzz

I don't have an A330 manual, closest is 777. In the 777 turbulent air penetration is 280knots / 0.82 mach at or above 25,000 feet. This is only marginally slower than average cruise (0.84 mach) - and still perhaps 100 knots, calibrated, from stall - plenty. IIRC, the plane detected the problems therefore the pilots would of been alerted and therefore switched to backups. If in extreme turbulence it may be possible for different instruments to react differently therefore giving conflicting readings.

Near the ground in a landing configuration, the plane stalls in the 130 knot range (don't know exact number, a light of pilots on this site can probably elaborate).

Probably close to 115 knots, maybe around 100 if very light. Not sure about clean, though, maybe closer to 200 knots? Reminds me of the Md-11, at heavy weights minimum clean speed (not stall) is around 280 knots.

[edit on 5/6/2009 by C0bzz]

reply posted on 5-6-2009 @ 01:04 PM by kilcoo316

Originally posted by solidshot
If Airbus feel that the accident could have been caused or aggravated by instruments giving a false reading and seem to think it may happen again as seemingly shown here should the aircraft not be grounded until this problem is fixed?

No chance.

Airbus has reissued guidelines to pilots after experts said the plane may have had false speed measurements.

A spokesman for Airbus said that a notice had been sent reminding Airbus air crews worldwide what to do when speed indicators give conflicting read-outs.

Spokesman Justin Dubon said that the inconsistent readings meant that "the air speed of the aircraft was unclear".

He said that in such circumstances, flight crews should maintain thrust and pitch and - if necessary - level off the plane and start troubleshooting procedures as detailed in operating manuals.

In my personal opinion, the different speeds are a red herring. The plane experienced immediate catastrophic failure, otherwise the pilots would have radioed a mayday.

My money remains on explosive decompression (*perhaps induced by multiple lightening strikes), causing structural failure of localised stringers, resulting in global structural failure and aircraft break-up.

Not much can be done about it, the A330 is amongst the safest aircraft ever built, but you cannot design for every potential contingency.

*For all we know it could have been a f**kin meteor hitting the aircraft - design for that!

reply posted on 5-6-2009 @ 01:26 PM by C0bzz

*For all we know it could have been a f**kin meteor hitting the aircraft - design for that!

Mount an IRST on the roof and use computers to find meteors, compute the trajectory, and automatically carry out evasive maneuvers, (hard if it's going mach 50).

Couldn't resist.

reply posted on 5-6-2009 @ 02:03 PM by Harlequin

reply to post by C0bzz

nah - have a pop up SM-3 launcher

reply posted on 6-6-2009 @ 02:30 PM by solidshot

Earlier on Saturday, the head of French air investigators said at a news conference north of Paris that the jet was due to have part of its airspeed sensor system replaced after the plane’s manufacturer, Airbus, had advised operators of some of its A330 aircraft to do so.

NYTimes

Will be interesting to see how this pans out, also why would they only tell some operators to replace their airspeed sensor systems? have these parts been replaced with newer systems on more recent aircraft or some other reason?

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